Apple Cinema 20" LCD (1680x1050) doesn't seem to work properly in X
on G5 with Radeon 9600, only on console, and doesn't work at all with ATI Radeon 7500 on x86-64 at all.
On the console radeonfb it runs in 8bpp, fbset reports:
mode "1680x1050-53"
# D: 100.000 MHz, H: 58.140 kHz, V: 53.339 Hz
geometry 1680 1050 1680 1050 8
timings 10000 16 16 16 16 8 8
rgba 8/0,8/0,8/0,0/0
endmode
Now, when run with fbdev driver, it looks really unreadable, although as
seen in the attached snapshot, the data ksnapshot took are fine.
When using the radeon Xorg driver, the display turns black (presumably powers
itself off) and will not come up until the machine is rebooted and firmware
reinitializes the ATI card.

Please file a bug in freedesktop.org bugzilla, so the other PPC/X developers
are aware of the issue, and it will get fixed in upstream CVS and included
in the 6.8.3 release.
http://bugs.freedesktop.org in the "xorg" component
Once you've filed the X.org report, please paste the URL here, so we can
track the issue there, and discuss with Xorg PPC developers centrally.
Once a fix gets checked into CVS on the stable branch, we'll review it
for consideration in our rpm packaging in future builds as well.
Thanks in advance.

If an upstream bug report has been filed for this issue, and you'd like
the X Devel team to track it for fixes, please update the bug with the
upstream bug URL, and reopen the bug and we will add it to our internal
tracker.
Setting status to WONTFIX.